1. Field of the Invention
The present invention relates generally to disposable colorimetric sampling devices, and, more specifically, to a user-friendly, simple to use, disposable colorimetric sampling device for the detection of one or more specific potentially harmful substances in an environmental or biological sample.
2. Description of the Related Art
Diagnostic assays for the determination of specific proteins in biological and environmental samples are commonly used across various industries (environmental, biotech, healthcare, food, etc). With the increased awareness of health and wellness in the home and other indoor environments and the outdoors, there is growing interest in assessing the presence or absence of potentially harmful substances and how efficacious household cleaning products are in denaturing or destroying molds, allergens viruses, bacteria, and other proteins known to cause negative human and animal health effects.
Colorimetric assays utilizing sampling devices for the detection of total proteins in biological samples are commonly used across various industries (biotech, healthcare, food, etc). Protein detection assays are available through biotechnology companies such as Pierce, Bio-Rad, and Biotrace International.
One such detection assay, described in U.S. Pat. No. 6,818,455 of May, et al., employs a porous carrier capillary device, sometimes referred to as a lateral flow strip, which provides mobilizable particulate labeled reagents for detection. Pregnancy test devices, well known to those of ordinary skill in the art, utilize lateral flow strips.
Prior art sampling and test devices utilizing lateral flow strips typically comprised a hollow base constructed of moisture-impervious solid material, such as plastic materials, containing a lateral flow strip that communicated indirectly with the exterior of the base through an absorbent wick which protruded from the base such that a liquid test sample could be applied to the wick and permeate therefrom to the lateral flow strip. The lateral flow strip typically included a mobile zone, containing a labeled analyte specific binding reagent, which was freely mobile within the mobile zone of the lateral flow strip when in the moist state. The lateral flow strip of the prior art further included an indicia zone, spatially distinct from the mobile zone. The indicia zone included an unlabelled specific binding reagent for the same analyte. The unlabelled specific binding reagent that was permanently immobilized on the lateral flow strip was not mobile in the moist state. The mobile zone and the indicia zone were arranged such that the liquid sample applied to the mobile zone of the lateral flow strip permeated into the indicia zone by capillary action. The presence of the analyte in the liquid sample was colorimetrically indicated in the indicia zone of the lateral flow strip as the labeled reagent permeated and become bound in the indicia zone. A user of the device observed the colorimetric results through a window in the base.
While these sampling devices were used effectively by trained users, the current devices and methods of detection were unsuitable for home diagnostic applications, because of their lack of user-friendly qualities for those not skilled in science or trained in the use of analytical devices. Further, the possibility of misplacing the multiple parts of these devices and the lack of an efficient means of distributing the devices to consumers at a low cost complicated the wide spread home use of the devices.
Further, these prior art sampling and testing devices were limited to use with liquid samples. The samples needed to be in a liquid form originally or the wick of the device needed to be separately wetted, through user manipulation, with a separately stored elution solvent, such as a liquid buffer, prior to sampling of dry surfaces of a sampling object of interest.
Accordingly, there is a need for improved methods and sampling devices for convenient use in a household for the rapid detection of proteins in specific molds, allergens, fungi, bacteria, or other protein-containing substances. More specifically, there is a need for the development of a sampling and testing device and method that are equally or superiorly reliable to the other options already available, but that are more conveniently distributable to a large number of untrained users, more conveniently usable in the home, and more easily disposed.